After four years, it appears the U.S. construction market has bottomed out and is beginning the slow climb out of recession. For many large U.S. design firms, this development is cause for both relief and celebration. But for other design firms, particularly in the public infrastructure markets, uncertainty about the future remains a constant.The signs of the recession's end can be seen in ENR's Top 500 Design Firms list. The Top 500, taken as
Arch dams, classically curved monoliths situated in narrow valleys, are not as common as other types of dams, such as embankment dams and gravity dams. ENR takes a look at some of the biggest arch dams in the world, both completed and under construction.